Foam proportioning inductor nozzles and tank systems are used in the so-called deluge system of fire fighting installations which provide a sprinkler or spray arrangement with overhead sprinkler heads which are arranged to deluge or send down a spray of water or foam automatically upon sensing a fire condition. Such deluge systems are commonly used in aircraft hangers, large industrial buildings for soybean processing plants, chemical production facilities and in other areas where highly flammable fumes may be present. The deluge system is foam based and uses a variety of protein or AFFF (aqueous film foaming foam) based foams. Each such foam is subject to differing rates of supply, meaning that the proportion of the foam concentrate to water varies for each particular type of foam used.
It has been known to use inductor nozzles mounted atop foam concentrate supply tanks which are in turn mounted upon a ground floor of the hanger, industrial shop or the like and connected into the fire suppression piping system. Normally, an expensive piping bypass is run around the tank and nozzle combination, which isolates the inductor nozzle from the waterflow stream when the tank is being replenished with foam, as during a protracted fire. Also, the normal course of operation has been to remove and replace the inductor nozzle with another such inductor nozzle with a different size orifice for correct proportioning whenever a different type of foam concentrate is selected for use. The inductor nozzle is quite expensive and is a major factor in the high cost of a change-over to another type of foam, inducing some foam users not to switch to more preferable varieties of foam until required to do so by local ordinances, even though the justification to switch may become well known prior to enactment of new ordinances.
Accordingly, the present invention involves a foam proportioning inductor apparatus including a foam concentrate supply tank and an inductor apparatus mounted atop the tank. Situated between the inductor nozzle and the tank are water supply lines leading into the tank for pressurizing the tank and providing the driver for the foam concentrate and a foam concentrate outflow line from the tank back into the nozzle which carries the foam. In the foam concentrate outflow line is a pipe section providing a removable and replaceable orifice. Because the pipe section with the orifice is relatively inexpensive, it can be readily changed in lieu of changing to a more expensive inductor nozzle, thereby permitting the user greater flexibility in selecting the proper foam to be used as a fire suppressant when the industrial use is altered or new and more effective foams are developed. Further, the arrangement includes shut off valves in the supply line and the fluid concentrate outflow line which eliminate the need for an expensive and extensive bypass circuit to route water around the inductor nozzle during replenishment while the system is being used to suppress fires. The disclosed arrangement includes valves so that the fire fighter does not have to reroute the water flow around the inductor nozzle and tank while replenishing the tank with foam, leading to easier use and increased responsiveness.